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本帖最后由 细胞海洋 于 2014-5-5 08:45 编辑 + [9 ?# ]! N4 ]3 D% ?
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2014年5月1日 Nature! L' e) d: ?$ @% ?" @, w* G
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The striking motions represented in Heel Daoyin, a kinetic sculpture by Peter Jansen, are reminiscent of limb oscillations seen in the absence of presynaptic inhibition. Humans and other animals execute limb movements with a seemingly effortless precision that relies on sensory feedback and its refinement by inhibitory microcircuits. A new study identifies presynaptic inhibition in the spinal cord, a regulatory filter mediated by Gad2-expressing GABAergic interneurons that form connections with the terminals of sensory afferents, as part of a hardwired gain control system crucial for the smooth execution of movement. Thomas Jessell and colleagues demonstrate that activation of Gad2-expressing neurons inhibits neurotransmitter release from sensory afferents. Selective ablation of these neurons in mice causes pronounced oscillations during goal-directed forelimb reaching movements, a behaviour captured by a model of sensory feedback at high gain. Cover: Peter Jansen, www.humanmotions.com
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